THE INFLUENCE OF MECHANICAL FORCES ON THE GLYCOSAMINOGLYCAN CONTENT OF THE RABBIT FLEXOR DIGITORUM PROFUNDUS TENDON

The physical forces acting on the flexor digitorum profundus tendon of the rabbit were altered by anterior translocation of the tendon. The glycosaminoglycan (GAG) content was determined in regions of the tendon previously under tension or previously subjected to pressure. There was an increase in the GAG content in the original tension transmitting region. Initially this was due to increased hyaluronic acid and chondroitin sulfate content during the early remodeling phase. Later when tension was restored to the translocated tendon, the content of these two GAG decreased to normal values while the high overall GAG concentration was maintained by increased amounts of dermatan sulfate. Finally the dermatan sulfate content and the total GAG content returned to normal values. The original pressure bearing region showed a rapid loss of total GAG. This was mainly due to a loss of chondroitin sulfate component, and eventually the region showed a GAG composition similar to that of normal tension transmitting tendon. Replacement of the translocated tendon to its normal position resulted in a slow replacement of the GAG, particularly chondroitin sulfate, in the pressure bearing region. The extent of recovery appeared to be dependent on the length of time the tendon had been left in the translocated position. Attempts to form a new pressure bearing structure in another part of the tendon also resulted in changes in the proportions of the GAG, but little change in total GAG content.